US2516027A

US2516027A - Circuit breaker

Info

Publication number: US2516027A
Application number: US692338A
Authority: US
Inventors: William H Stuellein; Walter S Hawkins; Gayne D Gamel
Original assignee: Westinghouse Electric Corp
Current assignee: CBS Corp
Priority date: 1946-08-22
Filing date: 1946-08-22
Publication date: 1950-07-18
Anticipated expiration: 1967-07-18

Description

July 18 1950 w. H. sTUELLElN ETAL 2,516,027

CIRCUIT BREAKER Filed Aug. 22, 1946 2 Sheets-Sheet 1 ano/'68a ne Q amel M MMA ATTORN EY July 18, 1950 w. H. sTUELLElN ETAL 2,516,027

CIRCUIT BREAKER Filed Aug. 22, 1946 2 Sheets-Sheet 2 ATTORN EY Patented July 18, 1950 CIRCUIT BREAKER William H. Stuellein, East McKeesport, Walter S. Hawkins, Wilkinsburg, and Gayne D. Gamel, Verona, Pa., assigner-s to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application August 22, 1946, Serial No. 692,338

(Cl. 20G-88) 17 Claims. l

This invention relates to circuit breakers and more particularly, to circuit breakers of the type that are automatically operated instantaneously on heavy overload currents above a predetermined magnitude, and after a time delay on persistent overload currents of lesser magnitude.

One object of the invention is to provide a circuit breaker with an improved trip device which will automatically trip the breaker instantaneously in response to heavy overload currents above a predetermined value, after a relatively short time delay in response to overload currents in an intermediate range below said predetermined value and after a relatively long time delay in response to persistent overload currents of relatively low value.

Another object of the invention is to provide a circuit breaker with an improved electroresponsive trip mechanism having an armature movable in one direction by a thermally responsive element to eiTect tripping of the breaker after a relatively long time delay, the armature being movable in another direction independently of the thermally responsive element and under the control of a mechanical escapement device to eiiect tripping of the breaker after a relatively short time delay and a second armature operable independently of the thermally responsive element and the mechanical escapement device to eiiect instantaneous tripping ofthe breaker.

Another object of the invention is to provide a circuit breaker with a novel trip mechanism einbodying an electromagnet having a normally latched armature which is rotatable by a thermal element to effect unlatching of the armature and tripping of the breaker under certain circuit conditions the armature being operated under the control of a mechanical escapement device independently of said thermal element to trip the breaker under certain other circuit conditions and a second armature opera-ble independently of the thermal element and the mechanical escapement to instantaneously trip the breaker.

Another object of the invention is to provide a circuit breaker with an improved trip mechanism of the character described in the preceding paragraphs which is of rugged construction and reliable in operation.

The novel features that are considered characteristic of the invention are set forth in particular in the appended claims. The invention itself, however, both as to structure and operation, together with additional objects and advantages thereof, will be best understood from the following detailed description of a single embodiment thereof when read in conjunction with the accompanying drawings, in which:

Fig. 1 is a vertical sectional View through the center pole of a circuit breaker embodying the features of the invention.

Fig. 2 is an enlarged vertical sectional view of the trip mechanism, taken on line II-II of Fig. 3 and looking in the direction of the arrows.

Fig. 3 is a bottom view of the mechanism shown in Fig. 2, and

Fig. 4 is a horizontal sectional view taken on line IV-IV of Fig. 2 and looking in the direction of the arrows.

Referring to Figure 1 of the drawings, the circuit breaker is provided with an operating mechanism common to all of the poles which is mounted in a U-shaped main frame I6 having spaced sides Il (only one being shown) rigidly connected by a cross member I9. rIhe frame I6 is mounted on the central portion of a base I I of insulating material and is secured thereto by means of bolts 2l and 23. The outer ends of the sides Il of the frame are rigidly connected by a cross member 25.

The bolt 23, extends through the base and the cross member I9 and serves to rigidly secure a connector 2'! of conducting material to the cross member and to the base I I. A shaft 29 extending through an opening in the connector 2l' and through openings in the sides of the frame I6 pivotally supports a pair of spaced arms 3l (only one being shown) having their free ends integral with a contact arm 30 for the center pole. The contact arms 3d (Fig. l) for the outer poles are identical with the arm 3U for the center pole but are not provided with arms 3 I. The contact arms for the outer poles are rigidly secured to a tie bar 6l which extends across all of the poles and which is clamped to the center pole contact arm 3Q by means of a split clamp l@ and a screw 1I. The three contact arms 3G are thus mechanically connected for movement together. Rectangular tubes @9 of insulating material between the tie bar El and contact arms 30 for the several poles serve to insulate the three movable contact arms and their associated contacts from the tie bar 6l.

The movable contact structures and the stationary contacts for the several poles are alike and therefore only the center pole contact means has been shown. The contact arm Si! for the center pole pivotally carries a main movable contact member 47 and a movable arcing contact member 55. The main contact member ll is pivoted on a pivot pin 49 supported in projections 5I of the contact arm 3l), and the movable arcing Contact member 55 is pivoted on a pivot pin 5l supported in projections 59 of the arm 3b. The main movable contact member lll carries a contact 53, and a. contact 35 is secured to the arcing contact member 55. These

contacts

33 and 35 are adapted to respectively engage fixed contacts 3S and 3l secured on a conductor il which is in turn secured to the base II by means of bolts 43. The conductor ll extends upwardly and is bent at right angles, the bent portions extending through an opening in the base I I to form a terminal connector 45.

A spring 53 compressed between a spring seat on the contact arm 3l) and a spring seat on the main contact member l1 provides contact presend thereof which acts to limit counterclockwiseV rotation of the arcing contact member 55 about its` pivot when the contact arm 3|) is moved to open the contacts. Counterclockwise movement of .the main contact member 61 is limited by a ,projection 13 thereon striking the body of the contact arm 38. The adjustment of the nut 15 on the rod 5| is such that the arcing contacts 35-31 open after the main contacts 33-39 open during an opening operation of the circuit breaker, and close before the main contacts close during a closing operation. y

When the contact arm 3|) is operated to open the contacts, the arc across the arcing contacts 35-31 resulting from the rupture of the current is drawn into an arc extinguisher indicated generally at 15- where the arc is cooled and extinguished. Any suitable arc extinguisher may be employed, the one illustrated comprising, generally, a stack of slotted plates (not shown) of magnetic material disposed adjacent the paths of travel of each of the arcing contacts 35. The platesserve to draw the arc towards the ends of the slots where it is broken up into a plurality of short arcs which are quickly cooled and extinguished.

The movable -arcing contact member 55 is connected by a nexible shunt conductor 11 to the main contact member 41, and another flexible shunt conductor "l5v connects the main contact member 41 to the connector 21. The connector 21 for the center pole is secured to the cross meinber i9 of the frame I6 by the bolts 23, and the connectors 21 for the outer poles (not shown) are bolted to the base with a spacer (not shown) between the base and each of these connectors in order to align the members 21 of the outer poles with the corresponding member 21: for the center pole. A conductor |15, secured to a projection |11 oi the connector 21 by means of a bolt |19 extends downwardly therefrom and is secured to the upper end of an energizing coil |151. The lower end of the coil |61 is secured to a conductor |85 which, in turn, is secured to a conductor 8|. The conductor 8| is bent at right anglesV and extends through an opening in the base where it forms a terminal` connector 83 which, together with the terminal connector 45, serves to connect the pole of the breaker in an electrical circuit.

The electrical circuits for the several poles of the breaker are essentially the same. The circuit of eachxpoleextends from the corresponding terminal connector 45 through the conductor 4|, the main contacts .E3-39, the main contact meinber 41, the flexible shunt conductor 1S, the connector 21, conductor |15, coil |61, and the conductor 8 l: to the terminal connector t3. The circuit for the arcing contacts 31--35 extends from the terminal connector d5, through the conductor 4 |f, the arcing contacts 31-35, contact member 55, the flexible shunt conductor 11, the main contact lmember 51, and through the previouslydescribed circuit to the terminal connector 83.

Thecontact arms 30 are biased in a clockwise or opening direction by means of a pair of springs (only one being shown). These springs are tensioned between the center pole Contact arm 35 and a fixed pivot 81 supported in the main frame I5. In the closed position of the breaker, the center pole contact arm 3|! and consequently all of. the contact arms are releasably restrained in closed contact position (Fig. l) by means of a toggle and linkage mechanism which is collapsible to cause opening of the contacts. The toggle and linkage forms a part of the common operating mechanism.

This collapsible linkage includes a lever 89 pivotally mounted on a xed pivot 9| supported on the main frame I6. The lever 89 comprises a pair of levers rigidly connected by an integral cross bar ||1, and is operatively connected to the support arms 3| of the center pole contact arm 3|) by a main operating toggle comprising

toggle links

93 and 95. The toggle link 93 has Aone end pivoted on a pin Il supported on the lever 8S and the link 95 is pivoted on a pivot pin 99 on the arms 3|.

rllhe links

93 and 95 are pivotally connected by a knee pivot pin 91. The toggle link S5 comprises a pair of links rigidly connected by means of an integral cross bar ||5.

The free end of the lever 89 is pivotally connected by means of a link |53 to one arm of a lever pivoted on the xed pivot 81. The otherarm of the lever 65 is pivotally connected to a toggle link |01 of a tripping toggle comprising the link |01 and a toggle link |09, The link |09 is pivoted on a ixed pivot ||3 supported on the frame i6, and comprises a pair of links joined near the pivot ||3. by a yoke |23 provided with projections |25 and |21. The toggle link |81 comprises a pair of links connected by a yoke 19 having a bent portion to which is secured an extension |2| of insulating material. The toggle links |1 and |09 are pivotally connected by a knee pivot pin l The purpose of the extension |2| is to cooperate with a part connected to a manually operable handley Ill to manually trip the breaker in a manner to be more fully described later. rThe lever and the link |03 each comprise a pair of members rigidly connected by yokes substantially as illustrated.

The linkage just described serves to releasably hold the contact assemblage including the movable contacts for all of the poles of the breaker in closed contact position. In the closed position, the main operating toggle 93-95 is overcenter above a line through the center of the pins SQ-EBI, and a secondtoggle, one link of which comprises the overcenter links 93-95 and the other link or" which comprises the lever 89, is overcenter above a line through the center of the pins SS and 9|. The overcenter movement of the main operating toggle 93--55 is limited by the projecting end of the link 93 engaging the cross bar ||5 of the link 95.

With the main operating toggle 93-95 and the toggle comprising the links 93-95 and the lever 89 in the overcenter position, as shown in Fig. 1, the springs 85 bias the lever 82 in a clockwise direction. Clockwise movement of the lever B9, however, is normally prevented by the tripping toggle H11-|09 which is overcenter to the left ofr a line through the center of the xed pivot l 13 and the point of connection of the toggle link i111 with the lever |05. The toggle H11- |09 is biased to its overcenter position by a spring |28 tensioned between the yoke I9 and the xed pivot H3, The overcenter position of the tripping toggle IDT-|09 is adjustably determined by the projection of the yoke |23 engaging an adjusting screw |29 in the cross member 25 oi the frame. The tripping toggle HB1-|09 in its overcenter position, acting through the lever |05 and the link |93, prevents clockwise movement of the lever 89 and consequently holds the movable contact assemblage in the closed contact position against the biasing influence of the springs 85.

The tripping toggle H11-|09 is adapted to be moved overcenter outwardly in a direction to cause its collapse to effect opening of the con-- tacts by means of an overload trip device indicated generally at |33 (Fig. 1). The trip device is operable in response to overload currents in the circuits of the breaker to actuate a trip rod |35 and cause collapse of the tripping toggle IUT-|09. The trip rod |35 is slidable vertically through a shunt trip device |65. The shunt trip device forms an additional tripping means for tripping the breaker and is adapted to be energized from a suitable source, controlled from a remote point and in a manner well known in the art, to operate the trip rod and trip the breaker.

When operated either by the shunt trip device or by the overload trip device |33, the trip rod |35 is thrust upwardly and strikes the projection |21 of the yoke |23 and rocks the toggle link |09 clockwise about the xed pivot ||3. This movement of the link |99 causes collapse of the tripping toggle ||l1|39 permitting clockwise movement of the lever 89 which permits the springs 85 to rock the movable contact assemblage clockwise to open the contacts.

The main operating toggle 93-95 does not immediately collapse, but the force of the springs 35 applied through the contact arm Sli-3| and the main operating toggle causes collapse of the toggle comprising the links 93--95 and the lever v89 which results in a, clockwise movement of the lever 89. This movement is transmitted through the link |03 and the lever |05 to complete the collapse of the tripping toggle HB1-|09.

The clockwise or opening movement of the contact arm 3|) is arrested by projections (not shown) thereon striking portions |31 of the frame I6. At this time the rebound of the inertiaof the main operating toggle 93-95 and the parts of the linkage 89, |93 and |95 starts the main operating toggle overcenter in a direction to cause its collapse. By the time the knee pin 91 of the toggle has passed overcenter below the line 99||l| the weight of the parts acts to complete the collapse of the toggle 93-95 and causes the linkage 89, |93, |05 and the tripping toggle |91|9 to be automatically reset to their normal positions. The main operating toggle S33-,95 remains in collapsed condition until the contacts are closed.

The contacts are closed manually by operation oi the previously mentioned handle |4| The handle is rotatably mounted in a bracket |43 of insulating material secured to the outer end of the main frame I6. Operatively connected to the mechanism (not shown) operated by the handle, is a link |5i. The lower end of the link |5| is recessed and straddles a pulley-shaped projection |53 rigidly secured on a cross member |41 rigidly connecting the outer ends of a pair of spaced contact closing levers |45. These levers are disposed on the outside of the frame It and are pivotally supported on the ends of the fixed pivot 9| which project beyond the sides of the frame. The inner ends of the levers |45 are rigidly connected by a cross member |49. Spaced projections |52 extending from the center portion of the cross member |49 support a pivot pin |51 upon which is rotatably mounted a roller |55.

The contacts are closed manually by clockwise rotation oi the handle lill. This movement of the handle, through connections (not shown) thrusts the link |5| downwardly and due to its engagement with the projection |53, rotates the closing lever M5 in a clockwise direction. During this movement of the lever |45, the roller |55 engages the link 93 of the now collapsed main operating toggle 93-35 and moves this toggle to its overcenter position. Since at this time the tripping toggle HB1-|39 has been restored to its overcenter position, rotation of the lever 89 is prevented and consequently the force applied by the roller |55 to straighten the toggle 93-95 rotates the contact arm 3Q counterclockwise to close the contacts and to tension the springs 85. The clockwise movement of the closing lever |45 moves the toggle 93-95 overcenter above the line 99-l 0| so that the contacts are held in the closed position until the breaker is again tripped.

The circuit breaker may be tripped manually by rotation of the handle lili through a small angle in a counterclockwise direction from its neutral position. When the handle is rotated in tripping direction, a projection (not shown) on the link |5| engages the extension |2| on the yoke I9 of the toggle link lill and rocks the link counterclockwise about its point of connection with the lever |35. This moves the tripping toggle Mil-|39 overcenter in a direction to cause its collapse and eiects opening of the contacts in the previously described manner.

The construction of the circuit breaker as thus far described is substantially the same as that fully disclosed in Patent No. 2,337,565, issued December 28, 1943, to John W. May, and assigned to the assignee of the instant application.

As previously stated, the trip rod |35 is operated to effect tripping of the breaker by means of a current responsive trip device |33. There is a trip device |33 provided for at least two of the poles of the breaker but since the trip devices are alike only the one for the center pole will be described.

Referring to Fig. 2 of the drawing, each oi the trip units comprises an electromagnetic trip means indicated generally at itl, a mechanical escapeinent device indicated generally at |63 and a shunt tripping electromagnet |35. The electromagnetic trip means |6| comprises the energizing coil |51, a iixed core member |39, a time delay tripping armature |1| and an instantaneous trip'- ping armature |13. The upper turn of the energizing coil |91 is mechanically and electrically secured to the short conductor 'l5 which is similarly secured to the projection |11 ci the connector 21 and to the base il by means of a bolt |19, a spacer |8| oi" insulating material being provided to space the parts away from the base. The lower end of the energizing coil |61 is connected by means of a rivet |83 to the short conductor |35 which is secured to the terminal connector 83. The lower end of the fixed core member |69 is provided with feet |86 which are secured by means yof bolts |91 to the conductor 93,Y andthe conductor 93' is secured to toI thebase ofthe breaker by means of bolts |39. The -upper end of the fixed core member |99 is divided and straddles the projection |11 and the conductor |15, each portion being suitably secured to the spacer I8| one on each side of the conductor |15 thus insulating the upper end of the xed core member from the conductor.

Disposed in the cup-shaped member |91 is a cylindrical latch member 295 having an annular groove 291 therein into which extend opposing studs 299 (Fig. 3) carried on the legs of a U- shaped arm 21|. The bight of the arm 2|| is secured by any suitable means, as by welding, to the bight of a second U-shaped arm 2 I3 having its two arms pivoted on pivot pins 2|5'supported in the two legs of a U-shaped bracket 2|1. The bight of the U-shaped bracket 2|1 is secured by means of screws 2|9 to a cover 22| rigidly supported on the spacer |9| on the base The downwardly extending arms 2|3 between them support a bar 223 provided with trunnions 225 for pivotally engaging openings in the arms 2|3. An adjusting screw 221 rotatably supported in the bar 223 threadedly engages a block 229 (Figs. 2 and 4) having spring studs 23| extending horizontally from each side thereof. Springs 233 having their lower ends hooked over the spring studs 23! and their upper ends hooked over spring studs 235 projecting inwardly from the side members of the bracket 2li, serve to bias the lever 2| I-2 I3 in a counterclockwise direction and thus bias the latch member 295 downwardly against thebottoin of the member |91.

Mounted on the rod |93 for rotation therewith is a latch 231 disposed below and in latching engagement with the latching portion 239 of the latch member 295 to thereby latch the armature |1| in its unattracted position. In order to mount the latch 231 on the rod |93 for rotation therewith, a substantially square opening is provided in the latch 231 which engages a substantially square portion of the rod |93. A spring 29| (Fig. 2) compressed between the latch 231 and a shoulder on the sleeve |95 biases the latch 231 against the latch member 295 and a spring 243 compressed between the latch 231 and the member |89 biases the latch 231 in the opposite direction. The purpose of the springs 24| and 2&3 is to prevent rattle of the latch 231 which is slidable longitudinally on the rod |93 between the end of the sleeve |95 and the shoulder on the rod.

The armature.` |1|Vis rotated about its axsto unlatchtitselfy fromv the latch member 295by a helical bimetal element 245 having its lower end secured to the energizing coilV |91 by means of the rivet |83. The upper endoi' the bimetal element 245 is secured to a guide cup 241 rotatably mounted on the flanged innerv end of a short tubular shaft 249 supported in the upper leg of the xed core member |59. The shaft 249 is secured in placeby means of a nut 25|, The armature |1| is provided with a longitudinally extending slot 253 which cooperates with a lug 255 `secured to the upper end of the helical bimetal element 245. The lug 255 serves to rotate the armature |1| and the latch 231 relative to the latch member 295 to eiect unlatching of the armatureV |1| and the slot 253 permits tripping. movement of the armature after it is unlatched.

The instantaneous trip armature |13 is disposed in an opening in the armature |1|and is biased against the member |99 by means 0f a spring 251 coiled about the armature |13 and compressed between the shouldered upper end of the armature |1| and a ange on the lower end of the armature |13. The armature |13 is tubular and is secured to a rod 259 having a l shouldered upper endupon which is disposed a washer 29|. A guide sleeve 293 surrounding the rod 259 and disposed between the armature |13 and the washer 29| has a sliding t in the tubular shaft 299. A flanged nut 295 is threaded onto the end of the rod 259. A lever 291 is pivotally mounted on a pin 299 supported in the two arms of a U-shaped bracket 21| which is secured to the upper leg of the Xed core |99. One end of the lever 261 is bifurcated and straddles the rod 259 between the washer 25| and the` ilanged nut 295. As will hereinafter be described upward movement of either of the armatures |1| or |13 rocks the lever 261 clockwise to effect tripping of the breaker.

When the lever 261 for any pole ofthe breaker is operated it acts through a trip bar 213 and the mechanical escapement device I 93 to actuate the trip rod |35 to trip the breaker. The trip bar 213 is rotatably mounted in spaced arms 215 projecting from a frame 211. The frame 211 is rigidly secured to the lower leg of a' U-shaped core member 219 for the shunt trip magnet |95 and supports an integral housing 299 in which the mechanical escapement is mounted. The upper leg of the core member 219 is rigidly secured to formed portions 29| (Fig. 1) of the side member I1 of the main frame I9. The shunt trip magnet |55 is provided with an energizing coil 293 and a movable armature 295 which normally rests on a stop 291 supported in the side walls of the housing 289. The armature 295 is attached to a tube 289 surrounding the trip rod |35. The shunt trip coil 293 may be energized from any suitable source, and, when energized, moves the armature 285 and the tube 299 upwardly to strike the projection |21 (Fig, l) and trip the breaker in the previously described manner.

A U-shaped member 29| (Figs. 2 and '3) mounted on the lower end of the trip rod |35 embraces a pin 293 carried between a pair of spaced plates 295 which are pivotally mounted on a pin 291 supported in the side walls of the housing 299. The plates 295 are provided with shoulders 299 which are biased by means of a spring 39| against a pin 393 mounted in a pair of spaced arms 395 also pivotally-supported on the pin 291. One end of the spring 39| is attached to a pin 301 supported between the plates 295 and the other end of the spring is hooked through an opening in a portion of the housing 280. The spaced arms 305 are operatively related to one arm 300 of a lever 309 secured by means of a screw 3|| to the trip bar 213 for rotation therewith. A pair of springs 3|3 disposed one on each side of the lower end of the lever 309 surround spring guides 3|5 having one end pivctally mounted on a pin 3|1 projecting from both sides of the arm 308. The other ends of the spring guides are provided with longitudinal slots 3|9 embracing the pin 303 The other arm 32| of the lever 309 is disposed to be engaged by the rounded head 323 of an adjusting screw 325 threaded into the lever 261 and locked in adjusted position by means of a lock nut 321.

The mechanical escapement time delay device |53 (Figs. 2 and 3) comprises an escapement wheel 329 and an inertia member 33|. The Wheel 329 is rotatably mounted on a shaft 333 supported in the side walls of the housing 280 and the inertia member 33| is mounted for oscillation on a pin 335 supported in the two arms o1 a Ushaped lever 331 which is pivotally supported on the shaft 333. Between them the arms 305 support a pin 339 upon which is mounted a roller 34| which engages a slot 343 in the escapement wheel 323l thus operatively relating the escapement device to the trip mechanism.

The trip device |33 provides for tripping the breaker in response to overload currents in three ranges after a time delay commensurate with each range of overload currents. The time delays are herein dened as long time delay, short time delay and instantaneous tripping. The ranges of overload current may be arbitrarily deiined as low range up to fteen times normal rated current; intermediate range between fteen and thirty times normal rated current; and instantaneous tripping thirty times normal rated current or over, or short circuit.

The operation of the trip device, assuming the occurrence o1 an overload current in the low range, is described as follows: when the coil |61 is energized in response to a persistent overload in the low range the armature |1| is attracted upwardly in a direction to effect tripping of the breaker. It will be remembered that the armature is latched by means of the

latch members

205 and 231 to the lever 2| |-2 |3 which is restrained in the position shown in Fig. 2 by the springs 233. The energization of the electromagnet in response to overload currents in the low range is insuiicient to overcome the tension of the springs 233, consequently, the armature |1| does not immediately move upwardly. "if the overload persists, however, the bimetal helix 245 becomes heated and, since the lower end of the bimetal is secured to a fixed member, the upper end carrying the lug rotates about the axis of the rod 259. The upper end oi the bimetal helix is secured to the guide cup 241 and to the lug 255, consequently, the guide cup 231 will rotate with the upper end of the helix 245 and, since the lug 255 engages the slot 253 in the armature |1|, the armature will also rotate with the upper end of the bimetal helix. Since the flanged member |89 is secured to the armature |1|, this member together with the latch 231 will rotate therewith relative to the latch member 205 which is prevented from rotating by means of longitudinal projection 345 (Fig. fi) on the member |91 engaging in longitudinal slots in the latch member 205. After the armature |1| has been rotated, a predetermined distance by the bimetal helix 245 the latch 231 is brought into alignment with an opening 341 in the latch member 305 and is unlatched therefrom, whereupon the armature |1| is moved upwardly in tripping direction by the already energized electromagnet. As the armature |1| moves upwardly, it moves the instantaneous tripping armature |13 and the rod 259 therewith and rotates the lever 251 clockwise about its pivot 269. As the lever 291 rotates, the head 323 of the screw 325 engages the arm 32| of the lever 309 and attempts to rotate this lever in a counter clockwise direction. The energization of the electromagnetic trip device |6| in response to overload currents in the low range is insuflicient to compress the springs 3|3, consequently the force applied to the lever 309 is transmitted through the springs 313 to rotate the arms 395 in a counterclockwise direction and, due to the engagement of the pin 303 with the shoulders 299 on the plates 295, rotates the plates also in a counterclockwise direction. The rotation of the arms 305 and of the plates 295 is retarded by the escapement device |63. Due to the pin and slot connection 34|-343 the counterclockwise rotation of the arms 305 applies a force to rotate the escapement wheel 329 in a clockwise direction. The escapement wheel 329 is provided with teeth 349 about a portion of its periphery which engage, and, upon clockwise rotation of the wheel 329, cause oscillation of the inertia member 33| to retard the rotation of the escapement wheel 329 and of the arms 305. This provides a short time delay in addition to the time delay occa sioned by the heating and rotation of the bimetal helix to unlatch the armature |1|. As soon as the last tooth 349 escapes the inertia member 33|, the arms 305 are free to continue their tripping movement unretarded. The armature |1| thereafter functions through the lever 261, lever 309, springs 3|3 and the plates 295 to thrust the trip rod |35 upwardly to operate the tripping toggle |01|09 and eiect opening of the breaker contacts in the previously described manner.

After the breaker contacts are opened and the coil |61 is deenergized, the armature |1| is restored to the position shown in Fig. 2 by the force of gravity, moving the lever 261 to its normal position and lowering the latch 231 to its position below the latch portion 239 (Fig. 4) of the latch members 205. Thereafter, as the bimetal helix cools, the armature |1| and the latch 231 are rotated to reenergize the latch 231 with the latch 205 in latching position.

The spring 30| (Fig. 2) is provided to restore the plates 295, trip rod |35, arms 305 and the escapement wheel 329 to their respective normal positions as shown in Fig. 2. The spring 30|, acting through the shoulders 299 of the plates 295 and the springs 3|3, also move the lever 309 to its operative position.

Upon the occurrence of an overload current within the intermediate range of overload currents, that is, between fteen and thirty times the normal rated current, the coil |61 is energized sufficiently to move the armature |1| upwardly against the tension of springs 233 without unlatching it from the lever 2| |2|3. Shortly after the start of the upward movement of the armature, the head 323 of the screw 335 engages the arm 32| and operates the lever 399 to compress the springs 3|3. The energization of the electromagnetic trip device |6| in response to overload currents in the intermediate range of overload currents is sufcient to compress the springs 3|3 but does not immediately effect triptiene? ping of the breaker. When the springs 3|3are compressed,l they apply a force to the arms 333 moving these arms and the plates 293 in tripping direction. This movement is retardedby the action oi the mechanical escapement device |53. However, since the mechanical escapement |63 provides the sole time delay on intermediate overloads, this time delay is relatively short, and tripping will be effected as soon as the wheel 329 escapes from the inertia member 33|.

When an overload current above thirty times rated current, or a short circuit, occurs the electromagnetic trip device |5| operates to instantaneously actuate lever 251 and effect instantaneous tripping of the breaker. Under this condition the armature |13 is immediately moved upwardly independently of the armature and the springs 233. Also, the tripping electromagnet, when energized in response to overload currents above thirty timesnormal, overcomes the springs 3|3 (Figs. 2 and 3) and operates the trip rod |35directly and independently of the mechanical escapement device to instantaneously trip the breaker. During such an operation the lever 339 is rocked counterclockwise with suicient force to compress the springs 3 3, the guides 3|5 sliding over the pin 333 without moving the arms 3535. A nose 35| on the arm 308 of the lever ,303 engages the spaced plates 295 and moves these plates counterclockwise to thrust the trip rod |35 upwardly and trip the breaker in the previously described manner. The instantaneous tripping action occurs at high speed and the mechanical time delay device does not have time to function.

Following an instantaneous tripping operation the lever 309 and the trip bar-233 are restored to their unoperated positions by the expansion of the springs 3|3 and the spring 33| serves to restore the plates 233 and the trip rod |35 to their normal positions. The armature |'i3 is restored to normal position by the spring Means are provided for adjusting the trip device in order to vary the amount of time delay on both long time delay tripping and short time delaytripping. rlhe adjusting means for the long time delay device comprises the member |31 in which the latch member 205 is slidably supported. It will be remembered that the member |37 is provided with a iiange |93 having concentric slots 233 therein through which the screws 20| extend to secure the member |91 to the fixed core member |39. By loosening the screws 23|, the member |31 may be rotated in either direction from the position in which it appears in Fig. 3. Rotation of the Ymember |97 (Fig. 4) through the projections 335 which engage the longitudinal grooves in the latch member 285, the latch member is rotated relative to the latch 23|'. This Varies the amount of deflection required of the bimetal helix 2135 before the armature |l| is unlatched and actuated to trip the breaker.

Indicating means is provided to indicate the setting of the member |97. The indicating means comprises an indicating wheel 353 (Figs. 2 and Y3) mounted on a vertically disposed shaft 355 supported for rotation in ears 351 formed inwardly from the bracket 2|?. A cotter pin 359 extending through an opening in the upper end of ythe shaft 353 above the upper ear 33t supports the shaft and wheel 353 in position. The wheel 353 is provided with teeth about a portion of its periphery which mesh with teeth on the flange |99 so that when the member |91 is rotatably adjusted the wheel`333`is also rotated. The ledge lf2 of the wheel3`53 is visible through `asight 'opening ina name plate-33| 'suitably secured to the bracket 2li andbears indicia designating the setting of the adjusting device.

The amount of time delay provided by the mechanical escapement'device |63 may be varied by moving the inertia member 33| lrelative to the escapement wheelV 329. Referring to Fig. 2, it may be seen that the wheel 329 is provided with teeth about a portion only `of its periphery. Movement of the inertia'member 33| circumferen'tially relative to th'eescapement whe'el'329 'varies the number 'of teeth lwhich must actuate the inertia member before the wheel 329 escapes therefrom and permits operation of the trip rod |35 to trip the breaker. Threadedly engaging the connecting portionof the U-shapedlever 331 which supports the inertia member 33| is a screw 333 which also engages in one of a series of openn ings 365 in the' portion of the housing 28B which is` concentric nwith the 'shaftV 333. To adjust the inertia member,`the screw 333 is removed and the lever 337.' is rotated in either direction to the desired position. The screw 333 is then reinserted to retain the l'ever33i and the inertia device 33| in the selectedpo'sition. In order to obtaina ne adjustment of the escapement device there is provided a stud '337 which threadedly engages the housing 233 and is 'locked in 'position by means of a lock nut 333. rThe upper end of the stud 361 is disposed in the path of the roller 34| and therelby acts as a li'mlt stop for the escapement wheel 323. `By loosening the llock 'nut 369 the Stud 361 may be screwed in and out thereby vvarying the positionof thewheel 323 relative to th-e'inertia member 33|.

Itwas previously set forth that, in response to overload currents in the intermediate range of overloads, the armature 'i'H is operated to trip the breaker without unlatching it from the springs2`3`3. In order to operate in this manner the current value must be high enough' to overcome the tension of the springs 233, that is, a minimum of iteen times normal rated current. The minimum overload current required to operate the armature without Vunlatc'hing'may bervari'ed by varying the tension of the springs 233. This is accomplished 'by turning the screw 221i (Fig, 2) thus moving the block 229 to which the lowei` ends of the springs'233 are attached to increase or decrease the tension of the springs.

It will be understood'that Ythe limits'of the intermediate range of overload currents (fteen to thirty times normal) are merely vby way of example, and these may be varied as will be readily understood'by those skilled in the 'art to which the invention appertains.

Having describedI the invention in accordance with the patent statutes, it is to be understood that various changes andmo'd-iiications may be made therein without departing from some of the essential features of the invention. 'It is, therefore, desired that the language of the appended claims be given as reasonably broad interpretation as the prior art permits.

We claim as our invention:

1.In a circuit breaker comprising relatively movable contacts, trip means operable to eiect opening of said contacts, said trip means 'comprising an electromagn'et having an armature movable in one direction to trip the'breaker, latch means for latching 'said armature against tripping movement, thermally responsive means operable when heated a 4predetermined amount 'in'response to 'overload currents to rotate said 13 armature to unlatch said armature, and means operated by said armature to cause tripping of Said breaker.

2. In a circuit breaker comprising relatively movable contacts, trip means operable in response to overload currents to effect opening of said contacts comprising electroresponsive means including an armature movable longitudinally to cause tripping of the breaker, means releasably restraining said armature against tripping movement, and thermally responsive means operable when heated a predetermined amount to rotate said armature to effect release of said armature from said restraining means and thereby permit longitudinal tripping movement of said armature.

3. In a circuit breaker comprising relatively movable contacts, trip means operable in response to overload currents to effect opening of said contacts comprising electroresponsive means including an armature movable axially to cause tripping of the breaker, means releasably restraining said armature against tripping movement, and thermally responsive means comprising a bimetallic helix operable when heated a predetermined amount to rotate said armature to effect release of said armature from said restraining means and thereby permit tripping movement of said armature.

4. In a circuit breaker comprising relatively7 movable contact means, trip means operable in response to overload currents to effect opening of said contact means comprising a solenoid having a core member movable longitudinally to eiect tripping of said breaker, means releasably restraining said core member against tripping movement, thermally responsive means operable when heated a predetermined amount to rotate said core member to cause release of said core member from said restraining means.

5. In a circuit breaker comprising relatively movable contact means, trip means operable in response to overload currents to effect opening of said contact means comprising a solenoid having a core member movable longitudinally to effect tripping of said breaker, means releasably restraining said core member against tripping movement, thermally responsive means comprising a bimetal helix operable when heated a predetermined amount to rotate said core member to cause release of said core member from said restraining means.

6. In a circuit breaker comprising relatively movable contact means, trip means operable in response to overload currents to cause opening of said contact means comprising electroresponsive means including an armature movable in one direction to cause tripping of the breaker, means releasably restraining said armature against tripping movement, thermally responsive means for rotating said armature to eiTect release of said armature from said restraining means, and means for adjusting said restraining means relative to said armature to vary the releasing time of said armature.

7. In a circuit breaker comprising relatively movable contact means, trip means operable in response to overload currents to effect opening of said contact means comprising a solenoid having a core member movable in one direction to cause tripping of the breaker, means releasably restraining said core member against tripping movement, thermally responsive means operable when heated to rotate said core member to cause release of said core member from said restraining means, and means for adjusting said restraining 14 means relative to said core member to vary the amount of rotation required to effect release of said core member.

8. In a circuit breaker comprising relatively movable contact means, trip means operable inl response to overload currents to effect opening of said contact means comprising a solenoid having a core member movable in one direction to cause tripping of the breaker, means releasably restraining said core member against tripping movement, thermally responsive means comprising a bimetal helix operable when heated to rotate said core member to cause release of said core member from said restraining means, and meansl for adjusting said restraining means relative to said core member to vary the amount of rotation required to effect release of said core member'u 9. In a circuit Abreaker comprising relatively' movable contact means, a trip device operable in response to overload currents to cause opening of said contact means comprising an energizing Winding, a first armature movable axially to trip the breaker, means normally restraining said first armature against tripping movement, time delay means comprising a bimetal helix operable when heated in response to overload currents below a predetermined value to rotate said nrst armature to release said armature and eiiect tripping of the breaker after a time delay, and a second armature operable in response to overload currents above said predetermined value to instantaneously trip the breaker independently of said iirst armature.

10. In a circuit breaker comprising relatively movable contact means, a trip device operable in response to overload currents to cause opening of said contact means comprising an energizing Winding, a rst armature movable axially to trip the breaker, means normally restraining said rst armature against tripping movement, time delay means comprising a bimetal helix operable when heated in response to overload currents be- 10W a predetermined value to rotate said iirst armature to release said armature and effect tripping of the breaker after a time delay, means for adjusting said restraining means relative to said first armature to vary the amount of time delay, and a second armature operable in response to overload currents above said predetermined value to instantaneously trip the breaker independently of said rst armature.

ll. In a circuit breaker comprising relatively movable contact means, a trip device operable in response to overload currents to cause opening of said contact means comprising an energizing Winding, a rst armature movable axially to trip the breaker, biased means normally restraining said rst armature against tripping movement, a first time delay means comprising a bimetal helix operable when heated in response to overload currents below a predetermined value to rotate said first armature to release said armature and eiect tripping of the breaker after a time delay, said biased means at times permitting axial tripping movement of said armature independently of said first time delay means, a second time delay means for retarding tripping movement of said first armature when said armature is moved independently of said first timedelay means, and a second armature operable inV response to overload currents above said predetermined value to instantaneously trip they breaker independently of said first armature.

12. In a circuit breaker comprising relatively movable contact means, a trip device operable in` i response vto overload currents to cause opening of said Contact means comprising an energizing winding, a first armature movable longitudinally to trip the breaker, biased means normally restraining said first armature against tripping movement, a first time delay means comprising a bimetal helix operable when heated in response to overload currents below a. predetermined value to rotate said rst armature to release said armature and effect tripping of the breaker after a relatively long time delay, said biased means permitting longitudinal movement of said armature independently of said first time delay means, a second time delay means for retarding tripping movement of said first armature with a relatively short time delay when said armature is .moved independently of said iirst time delay means, means for adjusting said restraining means relative to said first armature to Vary the amount of time delay provided by said first time delay means, anda second armature operable in response to overload currents above said predetermined value to instantaneously trip the breaker independently oi said iirst armature.

13. In a circuit breaker comprising relatively movable contact means, trip means operable in response to overload currents to effect automatic opening oi' said contact means comprising an energizing winding, an armature movable axially -to trip the breaker, biased means releasably restraining said armature against tripping movement, a first time delay means comprising a bimetal element operable when heated in response to overload currents to release said armature to eiect tripping of the breaker after a time delay, means for adjusting said restraining means relative to said armature to vary the amount of time delay yprovided by said first time delay means, said biased means at times permitting axial movement of said armature independently of said iirst time delay means, a second time delay means for retarding tripping movement of said armature when said armature is moved independently of said first time delay means, and means for adjusting said second time delay means to vary the amount of time delay provided thereby.

14. In a circuit breaker comprising relatively movable contact means, trip means operable in response -to overload currents to eiect automatic opening of said contact means comprising an energizing winding, an armature movable axially to trip the breaker,"means releasably restraining said armature against tripping movement, a, first time -delay means comprising a bimetal element operable when heated in response to overload currents to release said arma-ture to effect tripping of the breaker after a time delay, means biasing said restraining means to permit tripping movement of said armature independently of said rst time delay means, means for adjusting said restraining means relative to said armature to vary the amount of time delay previded by said rst time delay means, a second time delay means comprising a mechanical escapement mechanism for retarding tripping movement of said armature when said armature is moved independently of said rst time delay means, and means for adjusting said second `time delay means to vary the amount of time delay provided thereby.

15. In a circuit breaker comprising relatively movable contact means, trip means Operable in response to overload currents to cause automatic opening ci said contact meanscomprising an en,-

ergizing winding, an armature movable axially t trip ,said breaker, means releasably restraining said armature against tripping movement, a rst time delay means comprising a thermal element operable to rotate said armature to cause release of said armature, means permitting movement of said armature in tripping direction independently of said first time delay means, and a second time delay means for retarding tripping movement of said armature when said armature is moved in tripping direction independently of said first .time delay means.

16. In a circuit breaker comprising relatively movable contact means, trip means operable in response to overload currents to cause automatic opening of said Contact means comprising an energizing winding, an armature movable axially to trip said breaker, means releasably restraining said armature against tripping movement, a first time delay means comprising a thermal element operable to rotate said armature to cause release of said armature, means permitting movement of said armature in tripping direction independently of said rst time delay means, means opposing tripping movement of said armature independently of said first time delay means, means for adjusting said opposing means to vary the minimum overload required to move said armature independently of said first time delay means, and a second time delay means for retarding tripping movement of said armature when said armature is moved in tripping direction independently of said first time delay means.

17. In a circuit breaker comprising relatively movable contact means, a trip device operable in response to overload currents to cause automatic opening of said Contact means comprising an energizing winding, a rst armature movable axially to trip the breaker, means releasably restraining said first armature against tripping movement, a irst time delay means comprising a bimetal helix operable when heated in response to overload currents below a predetermined value to rotate said first armature to effect release of said armature to thereby effect tripping of said breaker after a relatively long time delay, means permitting movement of said first armature in tripping direction independently of said rst time delay means, a second time delay means for retarding tripping movement of said lirst armature with a relatively short time delay when said armature is moved independently of said first time delay means, and a second armature operable in response -to overload currents above said predetermined value to instantaneously trip the breaker independently of both of said time delay means.

WILLIAM H. STUELLEIN. WALTER S. I-IAWKINS. GAYNE D. GAMEL.

REFERENCES CITED The following references are of record in the iile of this patent:

UNITED STATES PATENTSy Number Name Date 2,337,565 May Dec. 28, 1943 2,340,973 May et al. Feb. 8, 1944 2,342,816 Peek Feb, 29, 1944 2,401,005 Lindstrom et al. May 28, 1946 2,414,526 Horn et al. Jan. 21, 1947 2,445,426 Gamel et al July 20, 1948